Unique attributes in a model

How do i ensure that a given attribute is defined the same for all entities. For instance, in the entity called TransactionPayment I have an attribute called transnum and uniquely identifies a transaction number. It is an integer and has a rule that it cannot be less than zero.

Next, I create a new entity called TransactionDetail and add an attribute called transnum and make it a nvarchar (25). Now i have two attributes both named transnum but both meaning different things and used in different ways.

Is there a way to prevent that? Once i create an attribute and give it some properties i want that attribute to mean the same thing no matter where it is used.